Plenary Lectures


PL01) INTRALAMINAR DAMAGE: MODELS AND EXPERIMENTS
By Prof. Dr. EVER JOSÉ BARBERO
Professor, Mechanical and Aerospace Engineering, West Virginia University, USA
ABSTRACT: Intralaminar damage in laminated composites is not only the first mode of damage encountered in most applications but also it precipitates other catastrophic modes of failure, such as delamination and fiber fracture. Also, intralaminar cracks are responsible for drastic increases of permeability, which exposes the fibers and the interlaminar interfaces to environmental attack, such as moisture, and thermomechanical loading by cryo-fluids, as well as compromising the imperviousness of the structure. Therefore, accurate prediction of initiation and evolution of intralaminar matrix cracks is fundamental for the prediction of ultimate material and structural strength, fatigue life, and so on. Along these lines, an overview of available modeling strategies will be presented, with a discussion of limitations, advantages, and disadvantages of each methodology. It will be shown that coupling intralaminar damage with a simple fiber fracture model allows for prediction of ultimate load capacity of open-hole tension tests. Key for those predictions are the objectivity of the model, which eliminates mesh dependency and enables damage localization. A novel application of acoustic emission, correlated against X-ray images, will be summarized. A methodology for experimental determination of invariant material parameters, i.e. fracture toughness, will be proposed. Emphasis will be made on the fact that just two material properties are needed to track transverse damage initiation and evolution, and that no characteristic length is needed to achieve objectivity.

  barberoSHORT BIO

PL02) TOHO TENAX NEW TECHNOLOGY DEVELOPMENTS
By Mr. JOE SPANGLER 
TOHO TENAX, USA
ABSTRACT: This presentation will bring information about current product portfolio and an overview of new technology developments in our group. Following new technologies will be discussed: (i) Tenax Thermoplastics: PEEK/CF reinforcements in the form of Woven Fabrics (TPWF) and Laminates (TPCL). It will be discussed material properties, supply forms and processing techniques. (ii) Tenax Dry Reinforcements: Discussions about Toho Tenax efforts developing dry reinforcements technologies for Infusion and RTM, challenged to meet the baseline of mechanical properties of aerospace prepregs. Technology involves multi-functional material solutions in preforming – by using binder technology -, toughening and lightning strike protection. (iii) Tenax Part-via-Preform: Discussions about short cycle processing of thermoset composite parts, using binder yarn technology, associated to automated preforming and HP-RTM processes. Toho Tenax established as a Tier-1 supplier of composite structures with this technology. (iv) Diversified Structural Composites – Curved Pultrusions: Discussions about state of art of technology in terms of manufacturing of curved pultrusions and application possibilities in aerospace and industrial applications.

   rodrigoSHORT BIO

PL03) NOVEL MULTI-SCALE CARBON NANOTUBE HYBRID COMPOSITES: PROCESSING, CHARACTERIZATION AND APPLICATIONS IN SMART SENSING
By Prof. Dr. ERIK THOSTENSON 
Associate Professor, Department of Materials Science and Engineering and Center for Composite Materials, University of Delaware, USA
ABSTRACT: Since carbon nanotubes were first observed over two decades ago considerable research has focused on exploring the unique physical and mechanical properties of this novel material. Their high stiffness and extraordinary strength, the ability to sustain large elastic strain, as well as their high aspect ratio and low density have enabled many potential applications, such as reinforcements for structural and functional composites, probe tips for atomic force microscopes and components in nanoelectromechanical systems. This presentation highlights recent research in processing, characterization and modeling of electrically-conductive carbon nanotube-based composite materials with an aim at establishing their fundamental structure-property relations. Because carbon nanotubes have diameters three orders of magnitude smaller than traditional advanced fibers there is unique opportunity to create multi-scale hybrid composite systems where reinforcement scales are combined. Our recent research has developed a highly efficient and industrially scalable electrophoretic deposition technique for nanoscale hybridization. We have demonstrated that conducting carbon nanotube networks formed in a polymer matrix can be utilized as highly-sensitive sensors for detecting the onset, nature and evolution of damage in advanced polymer-based fiber composites. The potential of carbon nanotubes for in situ monitoring of damage accumulation in fiber composite structures will be discussed and recent research on utilizing carbon nanotubes in large-scale structures highlighted.

  

 

THOSTENSON
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PL04) NONLINEAR TIME-DEPENDENT BEHAVIOR OF BIO-BASED COMPOSITES: ACCOUNTING FOR DAMAGE, VISCOELASTICITY AND VISCOPLASTICITY
By Prof. Dr. JANIS VARNA 
Chair professor, Dept. of Engineering Sciences and Mathematics, Lulea University of Technology, Sweden
ABSTRACT: Developing reliable material models for natural fiber composites accounting for microdamage and time dependent mechanical response of constituents is a challenging task and many issues are still not resolved. In long and aligned fiber composites the microdamage is well defined and the first damage events are matrix and interface properties governed. In short and long fiber composites with a nonuniform orientation distribution of fibers, the orientation and size of damage entities are not well defined which additionally complicates development of mechanism based material models. The main sources of the inelastic bio-composites mechanical behavior are identified as: a) microdamage; b) nonlinear viscoelasticity; c) viscoplasticity. The presented paper summarizes the experience accumulated in development of inelastic material models for composites with natural fibers and bio resins and suggests testing methodologies for parameter identification in these models. Due to microstructural complexity the effect of the microdamage on mechanical behavior is quantified implicitly by measuring the composite stiffness degradation. To simplify analysis the damage development is assumed to be elastic process which, certainly, in some cases may be an oversimplification. It is shown that the reversible time dependent behavior can be successfully described as nonlinear viscoelastic using Schapery’s thermodynamics based framework. The irreversible strains developing with time at large stresses depend on stress history. In many cases they can be analyzed as viscoplasticity using the functional representation suggested by Zapas. Predictive ability of models is demonstrated in many experiments. Effect of temperature and moisture on behavior of bio-composites is demonstrated.

 

 

varnaSHORT BIO

PL05) KEVLAR®; ARAMID FOR OIL & GAS STRUCTURES AND COMPOSITES: LIGHTWEIGHT AND PROVEN RELIABILITY AGAINST TOUGH ENVIRONMENTS
By Dr. ADRIANO CÂMARA MENDONÇA
DUPONT Protection Solutions, Latin America
ABSTRACT: Celebrating the 50th anniversary of Kevlar®; aramid fiber invention by DuPont, we realize that the extreme versatility, advanced properties and market-driven science behind Kevlar®; keeps driving continuous innovation and helping Scientists and Engineers around the world push the barriers and solve the toughest problems on the industry. It is not different when we look to the advanced structures used nowadays in the Oil & Gas exploration. Demands are challenging, with tough requirements that sometimes even seem to be to be mutually exclusive: often high structural strength is key, yet flexibility is also crucial; stiffness plays an important role, but toughness cannot be compromised; on top of that, chemical resistance, fatigue performance and lightweight structures are always high ranked on the list of priorities. To face that, composite structures reinforced with Kevlar®; fibers have been long used to match the complexity and harshness of the applications. Kevlar®; is five times stronger than steel on the same weight basis, being extremely tough and resistant to sea water and several chemicals used in the O&G industry. The fiber has been the material of choice for use in Thermoplastic Umbilicals, Flexible Risers, Marine hoses and Reinforced Thermoplastic Piping, working as the core reinforcement of structures designed to last up to 25 years exposed to the very harsh conditions of the Oil & Gas industry, both on-shore and off-shore. This plenary will explain through examples in the Oil & Gas industry how the properties combination of Kevlar® can enable Engineers and Scientists to go beyond the limits on the most challenging projects.

  adrianoSHORT BIO

PL06) MULTI-SCALE APPROACH FOR COMPOSITE MATERIALS
By Prof. Dr. SUNG KYU HA
Dept. of Mechanical Engineering, Hanyang University, Korea

ABSTRACT: Light weight composite materials offer significant benefits to increasing fuel efficiency and lowering carbon dioxide emissions. However, material selection, design and manufacturing process of composites needs to be well understood and integrated to make full use of such benefits of composite materials. This presentation is to introduce the recent development of Multi-scale approach for such purpose, starting with modeling of constituents-fiber, matrix and interface (micro scale); up-scaled to tow and laminate level (meso scale); and then applied to both characterizing mechanical behavior and simulating manufacturing process of composites (macro scale). This way, time and cost associated with material characterization tests can be significantly reduced, helping designers shorten design cycles taking into account manufacturing process for the selected fibers and resin system. Recently the approach has been successfully applied to several areas of composites: (1) optimal design of automotive applications requiring short cycle process (2) the thermoplastics vs thermoset composites (3) impact behavior of braided and woven fabric composites (4) optimal design of large-scale wind turbine blades.

  

 sung SHORT BIO 

 

Keynote Speakers


KN01) FRP PIPE DEGRADATION DUE TO EXPOSURE TO TEMPERATURE AND PRESSURE
By Prof. Dr. JOSÉ ROBERTO MORAES D’ALMEIDA
Chemical and Materials Engineering Department, Pontifícia Universidade Católica do Rio de Janeiro, Rio de Janeiro/RJ, Brazil.
ABSTRACT: The use of non-metallic composites in offshore platforms is driven by the need to increase component life in corrosive environments. As a result, composites contribute to a lower demand for maintenance and greater operational continuity. However, composites have limitations when are exposed to high temperatures or to the combined action of pressure and temperature. One of the requirements of using composites offshore is to demonstrate that composite parts retain a significant level of mechanical integrity during and after a fire exposure, or after exposure to stress peaks. This work evaluates and compares the mechanical behavior of two composite materials after exposure to thermal degradation in a fire and a post-fire scenario. The work also explores the combined effect of stress and temperature on the residual strength of a FRP composite pipe.

dalmeidaSHORT BIO

KN02) EXPERIMENTAL CHARACTERIZATION OF THERMAL WARPING OF COMPOSITE LAMINATES 
By Prof. Dr. SERGIO FRASCINO MÜLLER DE ALMEIDA
Polytechnic School, University of São Paulo, São Paulo-SP, Brazil
ABSTRACT: It is well known that that thin composite laminates are prone to thermal warping. This effect can be explored to indirectly characterize the magnitude of the residual thermal stresses responsible for the warping. This can be done by, for example, manufacturing a non-symmetric laminate [0/90]T on a mold consisting of a flat surface. As the plate cools down from the cure temperature, the thermal stresses will cause bending. The curvature of a narrow strip within the design temperature range will provide information to evaluate the residual stresses magnitude. However, one relevant aspect of thin composite laminate manufacturing has been overlooked in the open literature on this topic. When using a vacuum bag for manufacture the thin plates, the layer next to the mold will have a matrix content higher than layer next to the absorber. Therefore, there is a variation of the fiber (or matrix) content along the laminate thickness that will affect the elastic and physical properties of the layers. Therefore, the initial curvature and bending stiffness of the plate will be affected. In this work, a [0/90]T carbon/epoxy square plate was manufactured. The borders of the plate were discarded to eliminate the non-uniform thickness region.Three specimens (8 mm wide strips) were cut along the two orthogonal directions. The variation of the curvature with temperature were experimentally evaluated using a digital camera and image processing. Also, a mechanical loading was applied to experimentally measure the bending stiffness of each specimen. The experimental results indicated that the difference of the rate of the change of curvature with temperature and the bending stiffness varied with the direction of the specimen by about 30%. It should be emphasized that the tool part interaction does affect the initial curvature of the specimens but does not affect the rate of the change of curvature with temperature and the bending stiffness. A finite element model of the plate was developed using micromechanics to support the analyses of the results. The studied effect is quite relevant for the estimation of the thermal residual stresses and for design and manufacturing of thin composite parts. In this case, warping effects should be taken into account even for symmetric laminates.

 

frascino
SHORT BIO

KN03) PROCESSING OF ALL-OXIDE CERAMIC MATRIX COMPOSITES
By Prof. Dr. DACHAMIR HOTZA
Interdisciplinary Laboratory for the Development of Nanostructures (LINDEN), Federal University of Santa Catarina (UFSC), Florianópolis/SC, Brazil

ABSTRACT: Ceramic matrix composites (CMCs) have attracted lots of attention for thermomechanical applications due to their damage tolerant fracture behavior. This is the result of toughening mechanisms, particularly crack deflection into fiber-matrix interface as well as subsequent fiber pullout and bridging. Among the different categories of CMCs, all-oxide systems have recently been in the focus of research because of their inherent high oxidation resistance compared to their non-oxide counterparts. This is interesting particularly at high temperature applications in oxidizing environments such as gas turbines. However, despite the considerable interest in oxide-oxide CMCs over the past decades, there are still barely production concepts which meet requirements in view of cost and performance. Up to now, production of all-oxide CMCs is dominated by a few small companies and research institutes in Germany and USA. Long manufacturing times, high material costs and multiple infiltration steps, in case of the most common CMC production routes, are some factors that lead to high prices and prevent a wider industrial application of these materials. Therefore, it is of vital importance to reduce production costs and to make all-oxide CMC manufacturing more flexible. In this project, routes and performance have been investigated in order to achieve this objective by using a combination of conventional powder metallurgy routes and well-known production concepts existent for manufacturing polymer matrix composites, e.g. a prepreg technology based approach. The manufacturing comprises the integration of commercially available techniques for the production of polymer composites with well-known powder metallurgy routes typical for ceramics. These materials exhibit a high flexural strength (~450 MPa in four-point bending) with remarkable high remaining loading capability when exceeding the max. strength, e.g. a very advanced damage tolerant behavior. Thereby, the strength degradation is stepwise due to a combination of toughening by fibers and by the layered structure; even at strains above 1 % the composites exhibit a retained strength of ~100 MPa.

 

hotza

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KN04) FULL BIOMASS UTILIZATION AIMING THE PRODUCTION OF HIGH PERFORMANCE MATERIALS

By Prof. Dr. ALCIDES LOPES LEAO
Dept. of Bioprocess and Bioengineering, College of Agricultural Sciences/FCA/UNESP, Botucatu/SP, Brazil
This talk discusses the possibilities of using biomass for several industrial applications, including biopolymers, biobased materials and biofuel. Also covers the potential conflict between materials/energy and food, cascading concept of biomass utilization and the use of residues. The innovation and R&D process in Brazil are discussed mainly toward the newest technologies for biomass conversion into materials or energy. Finally discuss the state of the art of biomass and agriwastes utilization in Brazil, going from chemical feedstock, biofuels and biobased materials or biobased composites, at macro, micro and nanoscales.

leao

SHORT BIO

KN05) CARBON NANOMATERIALS BASED POLYMER COMPOSITES AND SUPERCAPACITORS
By Prof. Dr. GLAURA GOULART SILVA

Centro de Tecnologia em Nanotubos de Carbono, Federal University of Minas Gerais, Belo Horizonte/MG, Brazil
ABSTRACT: Our research group is exploring carbon nanomaterials with unique electric, thermal, and mechanical properties, as well as high surface area, to uncover novel practical approaches for the production of advanced polymer nanocomposites and for the application in supercapacitors. We aim to contribute to the exploitation of carbon nanomaterials at the forefront of highly demanding fields, providing results with tested scale up. Carbon blacks, carbon nanotubes and graphenes are being produced and surface modified to allow the integration in the final materials and devices. These novel materials will be particularly attractive for those working in industrial harsh environments and to support strategies for alternative energy solutions.

 glaura

SHORT BIO